Workpiece vise support attachment for surface grinding machine

ABSTRACT

A tool grinder is provided with a workpiece support attachment having a pair of relatively slidable plates which are preadjustably positioned by rotation about an axis. The plates are connected by a lead screw adapted to be rotated by a hand wheel for relatively sliding them. After the grinding of one surface of a workpiece by the grinding wheel, a second surface is ground by sliding one of the plates in a direction away from the grinding wheel and parallel to the second surface. At the same time, the workpiece is oscillated relative to the grinding wheel to grind the second surface flat.

United States Patent Lorton [451 Aug. 1, 1972 [54] WORKPIECE VISE SUPPORT ATTACHMENT FOR SURFACE GRINDING MACHINE [72] Inventor: Calvin J. Lorton, 1319 Grand Ave.,

Dayton, Ohio 45407 [22] Filed: April 2, 1970 [21] Appl. No.: 25,106

[52! 11.8. CI. ..51/218A [51 1 Int. (.1. ..B24b 3/00 [58] Field 01 Search ..51/218, 216.6, 327, 122

[56] References Cited UNITED STATES PATENTS 2,394,202 2/1946 Pollard ..51/218 A 2,467,674 4/1949 Krueger ..51/218 A X 2,181,396 ll/l939 Edgar ..51/218 UX 2,885,912 5/1959 Alber ..51/327X 2,452,089 10/1948 Wiken ..51/216.6 UX 2,958,988 11/1960 Crosby ..51/216.6X

Primary Examiner-Harold D. Whitehead Attorney-Dybvig & Dybvig [57] ABSTRACT A tool grinder is provided with a workpiece support attachment having a pair of relatively slidable plates which are pre-adjustably positioned by rotation about an axis. The plates are connected by a lead screw adapted to be rotated by a hand wheel for relatively sliding them.

After the grinding of one surface of a workpiece by the grinding wheel, a second surface is ground by sliding one of the plates in a direction away from the grinding wheel and parallel to the second surface. At the same time, the workpiece is oscillated relative to the grinding wheel to grind the second surface flat.

2 Claims, 9 Drawing Figures PATENTEl'l-Aus I 1912 -JIE.6

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INVENTOR. CA L V/N J, LOH TON WORKPIECE VISE SUPPORT ATTACHMENT FOR SURFACE GRINDING MACHINE BACKGROUND OF THE INVENTION This invention relates to a surface grinding attachment and more particularly to a grinding attachment especially adapted for use in grinding tool bits although, as will become apparent, the device is capable of more general use.

Tool bits typically are designed with a first surface, the leading edge of which terminates in the grinding point or edge and asecond surface cut at an obtuse angle to the first surface. In use, the leading edge of the second surface is often designed to cut a chamfer. In forming a tool bit from a blank, the blank is normally fixed in a vise mounted by a surface grinding attachment on the work support table of a grinding machine. The vise is usually adjustable about either two or three axes. After the appropriate adjustments of the position of the grinding wheel and the vise, the first sur face of the tool bit is ground by moving the vise and, accordingly, the tool blank past the grinding wheel. In order to form the second surface, it has been necessary to change the orientation of the vise as well as perhaps the table. In practice, if there are a number of identical tool bits to be ground, one surface of all of the tool bits is first ground. The machine is then set up for grinding the other surfaces and then all the tool bits are again successively clamped 'to the vise for grinding the second surfaces. This is a time consuming, inefficient and, accordingly, expensive procedure.

Another problem encountered when grinding two surfaces is generally known as blending of the joining ends of the two surfaces. Considerable patience and skill is required to insure that the two surfaces meet at the prescribed angle. So-called blending attachments may be used which facilitate the change in set up for the grinding of two surfaces and which are intended to minimize the blending problem. Even with the use of a blending attachment, the machinist must exercise considerable care and frequently must use a coloring dye to assist in determining that the surfaces are properly blended.

Generally, the foregoing problems are encountered when grinding any two surfaces meeting at an angle less than 180 and other than 90. When the two surfaces meet at an angle greater than 180, radial attachments or other devices are used. In the special case of two surfaces meeting at a 90 angle, one surface can be ground in the normal manner and the other surface then ground by moving the workpiece holding attachment horizontally away from the grinding wheel by adjusting the position of the work table. To obtain a flat surface, the work table is also oscillated back and forth in a direction perpendicular to its direction of movement away from the grinding wheel. However, no satisfactory method or apparatus has been developed for grinding two surfaces meeting at an angle of less than 180 and other than 90 without setting up the machine between the grinding of the two surfaces.

SUMMARY OF THE INVENTION The primary objects of this invention are to provide apparatus for rapidly grinding two surfaces of a workpiece without repositioning the grinding tool or the workpiece. In accordance with this invention, a surface grinding attachment includes a pair of relatively slidable members which can be relatively moved after the grinding of a first surface to cause the vise and, accordingly, the workpiece to be correspondingly moved relative to the grinding wheel. The relatively movable members are conveniently moved by a lead screw mechanism interconnecting them. The preferred method of operation is to first cut the first surface and then incrementally move the workpiece relative to the grinding wheel while simultaneously oscillating the workpiece back and forth past the grinding wheel. The second surface is thereby formed true, fiat and smooth.

Still another object of this invention is to provide such an attachment with cooperating calibration means so that one knowing the angles of the two surfaces to be cut may pre-adjustably position the vise and the relatively movable members prior to the grinding of the first surface whereupon both the first surface and the second surface can be ground without further adjustment.

Other objects and advantages will become apparent from the following description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a portion of a tool grinding machine provided with a surface grinding attachment made in accordance with this invention and set up to grind the second surface of a tool bit blank;

FIG. 2 is a side elevational view of an adapter provided by this invention used in the surface grinding attachment shown in FIG. 1;

FIG. 3 is a cross sectional view of the adapter taken along section line 33 of FIG. 2;

FIG. 4 is another cross sectional view of the adapter taken along section line 44 of FIG. 2;

FIG. 5 is a plan view of a portion of the surface grinding attachment as viewed in the direction of arrows 5 5 of FIG. 1;

FIG. 6 is a side elevational view of a portion of the machine of FIG. 1 showing the relative positions of the tool bit blank and the grinding wheel and, by arrows, indicating the direction of movement of the blank when grinding a second surface;

FIGS. 7 and 8 are perspective views of vise support members used in the attachment of FIG. 1; and

FIG. 9 is a side elevational view of a portion of a ground tool bit.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1 in greater detail, a portion of a tool grinding machine generally designated 10 is illustrated and includes a grinding wheel 12 fixed to a spindle l4 rotatably mounted in a housing 16 and driven by a motor (not shown) located in a motor housing 18. The housings 16 and 18 are mounted by swivels 20 and 22 upon a vertically movable column 24. As well known to those familiar with tool grinding machines, the movement of the column 24 provides a height adjustment and the swivels 20 and 22 provide adjustment of the orientation of the grinding wheel 12. A further adjustment is provided by a pivotal support member 26 connected between the motor housing 18 and the swivel 20. The grinding wheel 12 may be shielded by a guard 28.

The grinding wheel 12 is supported adjacent a work support table assembly generally designated 30 mounted upon a machine bed 32. The support table 'assembly 30 includes a sliding support table 34 slidably mounted in ways (not shown) for movement in a horizontal plane both from right to left, as viewed in FIG. 1, and also toward and away from the'column 24. Manually operable control knobs 36 are provided for moving the slidable support table 34 to the right and left. Only one such knob 36 is shown. Normally there are four such knobs, two on each side of the machine. On the near side of the slidable support table'34 shown in FIG. 1, a T-slot 38 is provided in which are ad justably positioned stop members or dogs 40 adapted to engage a stop pin 42 mounted on a protective cover 44 for the ways (not shown) along which the slidable table 34 moves toward and away from the column 24.

The support table assembly 30 further includes a swivel table 46 swivelly mounted upon the slidable table 34. The mechanism swivelly mounting the swivel table 46 and the controls therefor are not illustrated, such being well known and forming no part of this invention. A T-slot 48 is formed in the top of the swivel table 46 for receipt of attachments adapted to support workpieces adjacent the grinding wheel 12.

The parts of the tool grinder illustrated in FIG. 1 and described above represent a simplified illustration of a conventional tool grinder such as the No. 2 cutter and tool grinder, Identification No. lDDD available from the Milling Machine Division of the Cincinnati Milling Machine Co., Cincinnati, Ohio. Such a tool grinder is shown in greater detail in the Service Manual and Parts List Catalog, publication number N-279l, copyright 1966, published by the same company. As will become more apparent, this invention is useful with many types of machines, especially tool grinders, wherein a work table is provided adjacent a grinding tool such as the grinding wheel 12.

For grinding tool bits and the like, a surface grinding attachment is normally used with the grinding machine 10. Two types of such surface grinding attachments are illustrated on page 72 of the aforementioned catalog, publication number N-279l. Such surface grinding attachments are adapted to hold a blank or workpiece in appropriate position for cutting metal therefrom to form a planar surface when the blank is moved past the grinding wheel. In accordance with this invention, such a surface grinding attachment is modified by an adapter to permit the cutting of a second surface of a tool bit or other workpiece.

. The surface grinding attachment of this invention is generally designated 50 and includes a work head clamp plate 52 bolted to the T-slot 48 of the swivel table 46 by T-bolts 54 and having a center, upwardly projected disc-shaped support pad portion 56. Mounted on top of the support pad portion 56 is a first or base vise support member 58 connected to the support pad portion 56 by a vertically extending screw (not shown). With reference to FIG. 7, the base support member 58 includes a circular, disc-shaped base plate portion 60, an upwardly extending arm portion 62 and a circular, disc-shaped mounting plate portion 64 having an exposed side surface lying in a plane perpendicular to the lowermost face of the base plate portion 60. Extending centrally through the face of the mounting plate portion 64 and the arm portion 62 is a screw receiving bore 66 for receiving a hex head screw 67 shown in FIGS. 4 and 5. Those familiar with the art will recognize that the work head clamp plate 52 and the support member 58 are conventional in surface grinding attachments. These parts correspond to the members designated by reference characters 18 and 30 on page 72 of the aforementioned catalog.

In accordance with this invention, the surface grinding attachment 50 further includes an adapter generally designated 68 which will be further described below and which is mounted by the screw 67 onto the base support member 58. In addition, the surface grinding attachment 50 includes a second or intermediate vise support member 70 mounted upon the adapter 68 by a screw 72 and a support body 74 for a vise generally designated 76. In FIGS. 1 and 6, the vise 76 is shown clamping a tool bit blank 78.

The intermediate support member 70 is constructed similarly to the base support 38 and includes a circular, disc-shaped pad portion 80 and a circular, disc-shaped mounting plate portion 82 having a bore 84 for receiving a screw 86 for attachment to the body 74. The vise 76 is not illustrated in detail because, again, the parts thereof are conventional and may be changed as desired. Briefly, the vise 76 is shown including a sliding jaw 88 to which a vise clamp plate 90 is connected. The position of the jaw 88 on the body 74 is determined by rotation of a lead screw (not shown) which may be manually rotated by a hand knob 92. The jaw 88 is shown abutting the tool bit 78 and holding it against a jaw plate 94 connected to the body 74 by screws 96. The body 74 and the parts of the vise 76 illustrated in FIGS. 1 and 6 may be identical to the parts numbered 1 11 and 15 shown on page 72 of the aforementioned catalog.

The surface grinding attachment 50, except for the adapter 68, is of the type commonly referred to as a universal vise because the support member 58 is adapted to be rotated about a vertical axis extending through the clamp plate 52, the intermediate support 70 is adapted to rotate about a horizontal axis extending perpendicularly to and intersecting the vertical axis of rotation of the first support member 58; and the body 74 with its associated vise 76 may be rotated about a third axis which is a horizontal axis perpendicular to and intersecting the axis of rotation of the intermediate support member 70. The surface grinding attachment 50 thus provides for an adjustment of the position of a workpiece, such as the blank 78, in three dimensions. In the usual surface grinding attachment, the support pad 56 of the clamp plate 52 is provided with indicia as illustrated calibrated in angles and the base plate portion 60 of the base support member 58 has reference marks whereby the orientation of the support member 58 about its vertical axis can be determined. The mounting plate portion 64 of the base support member 58 also is provided with a scale marked in degrees for determining the rotary position of the intermediate support member 70. As will be described below, the scale marked on the mounting plate portion 64 is also used in accordance with this invention for setting the desired position of the adapter 68. It is also conventional in surface grinding attachments to provide the mounting plate portion 82 of the second or intermediate support member 70 with a scale marked in angles for determining the orientation of the body 74 about its axis of rotation. Thus, given the angles to which a surface is to be cut from a blank, the parts of a surface grinding attachment can be preset whereupon, as the blank held thereby is moved past the front face of the grinding wheel 12, the surface will be properly ground.

The tool bit blank 78 shown in FIGS. 1, 6 and 9 has been ground away to form the desired first surface, designated 100. The adapter 68 provided by this invention is then used to assist in forming a second surface 102 (FIG. 9) projecting at an included angle of less than 180 from the first surface 100. It is to be understood that the blank 78 could have other ground surfaces, the designations first and second being used for convenience herein. The adapter 68 comprises a pair of relatively movable members which, for convenience, are identified herein as a fixed plate 104 and a movable plate 106. The fixed plate 104 is connected to the first or base support member 58 by the screw 67 and for this purpose the plate 104 has a centrally located, threaded bore 108 (FIG. 4) and a circular boss 110 received within a mating circular cavity 112 (FIG. 7) in the adjacent end face of the support 58. The movable plate 106 has a centrally located threaded bore 114 (FIG. 4) for receiving the threaded shank of the screw 72. It also has a cavity 116 for receiving a mating boss 117 (FIG. 8) projecting from the adjacent face of the intermediate support member 70. As will become more apparent, the mating surfaces of the bosses and cavities provide bearings for convenience in relatively rotating the parts.

The adjacent faces of the plates 104 and 106 interengage to form a longitudinally extending way which provides for relatively sliding movement of the plates 104 and 106 in a direction perpendicular to the axes of the threaded bores 108 and 114 therein. For this purpose, the movable plate 106 has an elongate tongue portion 118 fitting within a cooperating slot extending the length of the fixed plate 104. A gib 120 is located adjacent a side surface of the tongue 118 and gib adjustment screws 122 provided with jamb nuts 124 are threaded through apertures in the upper face of the fixed plate 104 for properly positioning the gib 120. The gib 120 functions in the well known manner to accommodate for wear between the plates 104 and 106.

A mechanism is provided for sliding the movable plate 106 relative to the fixed plate 104 including a lead screw 126 extending into an end face of the movable plate 106 and throughout the length of a cavity or chamber 128 formed therein. The lead screw 126 is provided with an externally positioned hand wheel or knob 130 having a hub 132 affixed to the external end of the screw 126 as by a pin 134. The free end face of the hub 132 abuts against the adjacent face of the movable plate 106 and the free end of the lead screw 126 abuts against the innermost end face 136 of the chamber 128. Accordingly, the screw 126 is prevented from axial movement further toward the center of the movable plate 106. The screw 126 is prevented from axial movement away from the center of the movable plate 106 by means of a retaining ring 138 abutting the outermost end face 142 of the chamber 128. The ring 138 is pinned or held relatively fixed to the screw 126 by one or more set screws 140.

A nut 144 is affixed to the fixed plate 104 as by screws 146. The nut 144 is located within the chamber 128 and has a threaded bore extending axially therethrough for receiving the lead screw 126. Because the nut 144 is fixed to the support member 58 by the fixed plate 104, the nut 144 cannot move. It is apparent, therefore, that manual rotation of the hand wheel or knob 130, and thereby the lead screw 126, will cause the lead screw 126 to travel perpendicularly toward or away from the longitudinal axis of the screw 67. Since the movable plate 106 must move axially with the lead screw 126, it will slide relative to the fixed plate 104.

With reference to FIG. 6, the surfaces and 102 are ground in the following manner. The grinding wheel 12 is preferably mounted for rotation about a horizontal axis which is in a plane perpendicular to the T-slot 48 and which is parallel to the top of the table 46. The position of the tool bit blank 78 relative to the grinding wheel 12 is thereafter determined entirely by angular adjustment of the various portions of the surface grinding attachment 50. As will become more apparent, the tool bit blank 78 is preferably so oriented that the first surface 100 is ground by the front face of the grinding wheel 12. The second surface 102 is then ground by the generally conical peripheral or rear face of the grinding wheel 12.

After the grinding of the first surface 100 by moving the blank 78 in a horizontal direction past the grinding wheel 12, the second surface 102 is ground by moving the movable plate 106 and, accordingly, the intermediate support member 70, the support body 74, the vise 76 and the tool bit blank 78 away from the grinding wheel 12. The movement of the movable plate 106 is obtained by rotation of the hand wheel and is in the direction of the longitudinal axis of the lead screw 126. By positioning the adapter 68 so that the screw axis is neither vertical nor horizontal, the movable plate 106 and, accordingly, the tool bit blank 78 is moved angularly away from the grinding wheel 12. In FIGS. 1, 5 and 6, the lead screw has been placed at a 45 angle relative to vertical. Hence, the tool bit blank 78 is moved at a 45 L angle upwardly and away from the grinding wheel 12. The direction of movement of the tool bit blank 78 is indicated by arrows 148 in FIG. 6. As the movement of the tool bit blank 78 in the direction of the arrows 148 continues, the tables 34 and 46 and, accordingly, the tool bit blank 78, are preferably oscillated to and fro horizontally in a direction perpendicular to the axis of the grinding wheel 12. Accordingly, the surface 102 will be ground flat by the rear surface of the grinding wheel 12. With a little practice a skilled machinist can grind a very smooth surface by repeatedly rotating the hand wheel 130 to move the blank 78 in increments while oscillating the blank 78 in a horizontal plane. It may be observed that if a flat surface is not necessary, the tool bit blank 78 could be moved away from the grinding wheel 12 by rotation of the hand wheel 130 while the table 30 remains stationary. The resultant surface, however, would have a concave curvature formed by the convex periphery of the grinding wheel 12.

The support pad portion 80 of the intermediate support member 70 has a scale graduated in angles in a manner identical to the scale on the adjacent mounting plate portion 64 of the base support member 58. Both scales are divided into four quadrants marked from through 90. The scale divisions shown in FIG. include a marking for each although in practice the scales would preferably be graduated in degrees or fractions of degrees. The top surface of the fixe'd plate 104 has a reference mark 150 thereon for alignment with the graduations on the scale appearing on the mounting plate portion 64. The movable plate 106 has a similar reference mark 152 immediately adjacent the scale on the support pad portion 80. The plates 104 and 106 preferably have a coplanar upper surface, as illustrated, spaced from the centerline of the bores extending therethrough by a distance equal to the radius of the adjacent scale divided parts of the support members 58 and 70 so that the reference marks 150 and 152 can conveniently be observed and accurately aligned with the scale divisions.

When preparing to use the adapter 68 of this invention, the desired angle of the second surface to be cut is preferably first set. This angle may be based upon or taken from the longitudinal axis of the workpiece 78. Accordingly, the adapter 68 is first positioned relative to the workpiece 78 at the proper angle for cutting the second surface by removing the screw 72 from threaded engagement with the movable plate 106. The intermediate support member 70 is then rotated until the reference mark 152 on the movable plate 106 is opposite the proper scale division mark on the adjacent intermediate support pad portion 80. Thus, in FIG. 5, the reference mark 152 is shown adjacent the indicator line for 45 on the scale of the support pad portion 80. The screw 72 is then returned into threaded engagement with the movable plate 106 sufficiently to clampingly affix the plate 106 and the intermediate support member 70 together. As should be apparent from the foregoing description, subsequent rotation of the hand wheel 130 would result in a movement of the movable plate 106 at an angle of 45 relative to the longitudinal axis of the workpiece 78 in a direction perpendicular to the axis of the screw 72. Since the workpiece 78 moves with the movable plate 106, it also would be moved at 45 to its longitudinal axis.

After the setting of the movable plate 106 relative to the intermediate support member 70 at the proper angle for forming the second surface to be ground, the proper setting for the first surface to be ground is obtained by removing the screw 67 from threaded engagement with the fixed plate 104. The plates of the adapter 68, the intermediate support member 70 and the vise body 74 with the vise 76 and the tool bit blank 78 are then rotated about the longitudinal axis of the screw 67. After thus rotating these parts to align the proper scale division on the mounting plate portion 64 with the reference mark 150, the screw 67 is tightened into firm threaded engagement with the fixed plate 104. As those familiar with the use of universal vises will be aware, the proper setting of the reference mark 150 with the scale divisions on the mounting plate portion 64 is dependent upon the orientation of the body 74 with respect to the mounting plate portion 82 of the intermediate support member 70 as well as the setting between the reference mark 152 and the scale divisions on the support pad portion 80. Accordingly, in order to adjust the fixed plate 107 relative to the base support member 58 to form the vertical first surface 100 with the reference mark 152 on the movable plate 106 set at 45, the adapter 68 is so rotated that the reference mark 150 is aligned with the 45 marking in the appropriate quadrant on the mounting plate portion 64. This position of the adapter 68 is illustrated in FIG. 5.

In contrast to the vertical surface illustrated, the first surface to be ground on a tool bit blank often lies at a small angle relative to vertical. To obtain the desired angle with reference mark 152 set at 45 as illustrated in FIG. 5, the parts may be first positioned as shown in FIG. 5 to bring the workpiece to a vertical position. The parts are then rotated about the longitudinal axisof the screw 67 to a position wherein the reference mark is aligned with a' scale division on the mounting plate portion 68 which is a few degrees more or less than 45, as the case may be. Thus in general, the proper angular relationship between the adapter 68 and the workpiece 78 is first obtained and the proper angular relationship between the workpiece and the bed of the machine is then obtained by rotating the adapter 68 relative to the base support member 58. lnview of the foregoing description, the manner of presetting the attachment 50 when the second surface lies at angles other than 45, is believed obvious. Other quadrants of the scale on the support portion 80 would be used if the orientation of the vise body 74 or of the grinding wheel 12 were different from that illustrated. Skilled machinists will also appreciate that so-called back angles could be obtained when grinding the first and second surfaces by appropriate rotation of the base support member 58 about its vertical axis.

From the foregoing discussion it is seen that the objects of this invention have been met. Aside from the adapter 68 and the intermediate support member 70, the parts illustrated in the drawing are all commercially available. The intermediate support member 70 differs from a typical intermediate support only in the inclusion of the graduated scale on the support pad portion 80 and the bore 114 extending therethrough for receiving the shank of the screw 72. Using the surface grinding attachment of this invention it is unnecessary to set up separately for grinding the second surface 102 and the difficulties of blending the two surfaces are obviated. Hence, parts formed from workpieces to be ground with this invention may be machined in volume in minimal time.

The grinding of two surfaces meeting at an angle of less than will usually be accomplished using the adapter 68 in the manner described above oriented as illustrated in FIG. 1. That is, in most cases the fixed adapter plate 104 will be mounted in an adjustably fixed orientation about a horizontal axis and the second or intermediate support member 70 will be mounted for rotation on the movable plate 106 for rotation about a horizontal axis. It will be noted that, because the movable plate 106 may be offset from the fixed plate support member the axis of rotation of the intermediate support member 70 may not be coincident with the axis of rotation of the fixed plate 104. In any event, these axes will be parallel if not coincident.

Occasionally, the adapter 68 would be best mounted upon its support for rotation about a vertical axis. Such an occasion would arise when the adapter 68 is used in conjunction with a radial attachment. When mounted about a vertical axis, the workpiece, of course, would are available with adapters for causing vertical oscilla tory movement of the grinding wheel and such oscillation would be desirable when the adapter 68 is mounted on its support for movement about a vertical axis.

Various modifications in the surface grinding attachment 50 of this invention will be apparent. For example, it will be noted that the movable plates 104 and 106 may be mounted upside down from the position shown in the drawings in which case the plate 106 would be fixed in relation to the table 46 and rotation of the hand wheel 130 would cause the plate 104 to be moved. The shape and construction of the relatively movable adapter plates 104 and 106 is not critical provided that some means, such as the lead screw mechanism, is available for relatively sliding them and provided that they can conveniently be attached to the adjacent portions of the surface grinding attachment.

It is also apparent that the sides of the plates 104 and 106 could be provided with cylindrical bosses upon which the scales may be marked in which case the reference marks 150 and 152 would be located on the adjacent surfaces of the support members 58 and 70. If it is desired to use the adapter 68 in a surface grinding attachment which is not provided with an intermediate support member such as the member 70, the vise support body 74 could be mounted directly upon the plate 106 provided that appropriate scale or reference mark means were located thereon.

The grinding wheel 12 illustrated is of the type known as a cup wheel. As previously mentioned, the first surface will normally be ground on the front face of such a wheel whereas the second surface is ground by the peripheral or rear face of the wheel. It will be appreciated that other types of grinding wheels such as disc-shaped wheels may be used in the practice of this invention. Ordinarily the first surface would be ground by the front face of such a wheel and the second surface ground by the peripheral surface thereof. Occasionally a circumstance may require that the rear face, which is on the far side away from the workpiece, would be used in grinding the second surface.

Although a preferred embodiment of this invention has been described, it will be understood that various said second axis, a second plate member, said first plate member and said second plate member having interengaging surface portions permitting linear moverqent of said first plate member relative to said secpnd p ate member and preventing rotation 0 said p ate members relative to one another, a lead screw mounted in axially fixed relation to one ofsaid plate members for rotation about an axis perpendicular to said second axis, said lead screw projecting beyond a margin of said one of said plate members, a nut affixed to the other of said plate members, said nut having a bore receiving a portion of said lead screw and operatively engaged therewith whereupon said second plate member may be moved in a linear direction relative to the first of said plate members by rotation of said lead screw. manually engageable means affixed to the end of said lead screw projecting beyond the margin of said one of said plate members whereupon said second plate member may be linearly moved relative to said first plate member by manually rotating said lead screw, a second support member mounted for rotation upon said second plate member about a predetermined axis which, during the linear movement of said second plate member relative to said first plate member, is parallel to said second axis, means for retaining said second support member on said second plate member in ad justably fixed relation to said predetermined axis, and means for supporting a workpiece vise on said second support member for rotation about still another axis which is perpendicular to said predetermined axis.

2. The apparatus of claim 1 wherein adjacent surfaces of said first support member and said first plate member are provided with cooperating indicia for indicating the angular orientation of said first plate member about said first axis and wherein adjacent surfaces of said second plate member and said second support member are provided with cooperating indicia for indicating the angular orientation of said second support member about said predetermined axis. 

1. In a workpiece holding attachment for a grinding machine, support means, a first support member mounted for rotation about a first axis upon said support means, a first plate member mounted upon said first support member for rotation about a second axis which is perpendicular to said first axis, means for retaining said first plate member on said first support member in adjustably fixed orientation with respect to said second axis, a second plate member, said first plate member and said second plate member having interengaging surface portions permitting linear movement of said first plate member relative to said second plate member and preventing rotation of said plate members relative to one another, a lead screw mounted in axially fixed relation to one of said plate members for rotation about an axis perpendicular to said second axis, said lead screw projecting beyond a margin of said one of said plate members, a nut affixed to the other of said plate members, said nut having a bore receiving a portion of said lead screw and operatively engaged therewith whereupon said second plate member may be moved in a linear direction relative to the first of said plate members by rotation of said lead screw, manually engageable means affixed to the end of said lead screw projecting beyond the margin of said one of said plate members whereupon said second plate member may be linearly moved relative to said first plate member by manually rotating said lead screw, a second support member mounted for rotation upon said second plate member about a predetermined axis which, during the linear movement of said second plate member relative to said first plate member, is parallel to said second axis, means for retaining said second support member on said second plate member in adjustably fixed relation to said predetermined axis, and means for supporting a workpiece vise on said second support member for rotation about still another axis which is perpendicular to said predetermined axis.
 2. The apparatus of claim 1 wherein adjacent surfaces of said first support member and said first plate member are provided with cooperating indicia for indicating the angular orientation of said first plate member about said first axis and wherein adjacent surfaces of said second plate member and said second support member are provided with cooperating indicia for indicating the angular orientation of said second support member about said predetermined axis. 